well I've successfully installed VLC but once I click the icon nothing pops up
this is what I get when trygin to run from command line:{vlc}
VLC media player 2.0.4 Twoflower (revision 2.0.3-289-g6e6100a)
[0x9fd138] main libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface.
[0xac0b78] qt4 interface error: Unable to load extensions module
Illegal instruction

Hello,
I did the same as you, it compiled but always crashed at launch, saying
something was wrong with qt4 (on my 2 gentoo boxes running amd64, one with gnome, the other with xfce)...
My configuration is very similar to yours, my system is also up to date.

I've just found out how to resolve the problem !

0) I do not use ~amd64 version anymore so I went back to vlc 2.0.3 version. I'll try an update later...
1) I used the recommended use flags + some more for my comfort...
2) I re-emerge qt-lib with gtkstyle flag (don't know if this has something to do with it, but I don't want to spend one more hour to rebuil it)
3) I uninstalled then emerged vlc

This "illegal instruction" was bugging me also. To fix it, I didn't do anything special, just reinstalled all qt and xfce related stuff (emerge -e qt-meta xfce4-meta --exclude 'glibc gcc') and then reinstalled vlc itself. After that things started to work. The funniest thing was, that the problem happened only under XFCE. Under sawfish, or i3 everything was working fine. Real mystery. It must be something that xfce offers and vlc tries to use.